Resistance unit.



No. 859,314.- PATEN'IED 0012.29', 1907.

o. MAUMILLAN. RESISTANCE UNIT.

EPE-Immun FILED 111:0.'1. 1905.

fz// iig/ww f f III/IIE l' lll/"mjy 1 mimi" WITNESSES. INVLNTDR.

- l EAMPUELLMAEMILLAN- UNITED sTATEs EETENT oEEIoE.

CAMPBELL MACMILLAN, OF SCI'IENECTADY, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RESISTANCE UNIT.

No. 869,314. Specification of Letters Patent. Patented Oct. 29, 1907.

Apiilontinn filed December ll 1905. Serial Nn. 289,931.

T all U-hOm l mail concern: matcrial having a negative temperaturecoefficient and Be it known that l. CAMPBELL M ACMILLAN, a subjectCommonly known is Seihi-@ducing resistance, Since of the King of (lrratBritain. rtsiding at Schenectady, its SpeciiiC resistance decimiss Wichincrease of mhh county of Schenectady. State of New York, haveinpeinture. Tim iiiii-ticiihii. mateijui used constitutes vented certainnew and useful linprovcnicnts in Ri ,i0 Pmi of my iiiviiii011 and may beof any of the W@11 6() sistamcoUnits. of which the followingisaspecifcation. known substancias imvimor the necessary pr0perties-This invention rulalis to resist-anc(l units for electric Among theseSubstances might be mentioned magnetcircuits and has for its object thoprovision of a unil, of it@ and Siiimii, the hihihi. heini., either inthe Cast or this character which will bc chrap and simple of con-,hohied h,i.iii rphis Stick 0f mami-ini I have Shown for struction. givea iride range of variation, which will iihrhoseshi iihisimtiiiii iii theShape if a tube'pmvided 65 withstand high tempi-mtime and at the sainetimal will with a spimi groove 2 although it is obvious it is not hilv@SUlClP-N Uu'f'llmlll Strength lo "Undlr it sul essential that thisgroove he on the inside of the tube, mill dumlilor in fact, that it begrooved at all so long as it accom- Mfr" Sllf'lllmlly my ln\"("llllm hasfor lts "ll-lufL lll@ plishes the object of having the turns of theconductor A Y l5 production oi a resistance unit having a m-gative tominContact with the resistance stick Within the 7() poraturc coeilicicntand which is somt-timos known as groove 2 is i Spiral conductor 3 WhichiS preferably a re soli-reducing resistance. Rrsistancc units of thistype Sishm Conductor Capable of Wii-hshindii'ig a comparaare not new inthe art but those produced up to tinl tively high iiipciiitum Thisciinductor may be PTCS'JU tlm@ 'have Uslmlly had Certain dlsilllflllllglwound on a mandrel and the material molded around This typo of rrsistancc has been made both in the forni it or any desired iiiemis maybe employed for bringing 75 0f S'Ck ICSSmUC@ and also l thelorm 0f lflexible con' the conductor into intimate relation with the material.ductor such as Wire or ribbon. Both the ficxihlc con- The ends of thembe are Closed by means of Caps 4 and ductor and the stick resistancehave their advantages 5 Whidi may he Oibeii 0i. any desired materialSecured and special uses and it is the object o my invention to to theends of tube- The ends 0f the Conductor gr combine these two forms intoan automatic Self-rcducbrought out ai, Opposite ends of the tube through80 lng resistance' l these caps secured thereto by means of bolts 6 and7 l Carrying Out my lmfntlon I provide a flexible which form terminalsfor connecting the unit in circuit. conductor, preferably in the orm'oia spiral, and means It Win be geen that when a Current is passed throughf or supporting the Same in COMMt Wtha resistance thisunititS-rosistancerwll be practially that o th, material llavlngahlgllnegativ@ temperatur@ Coelllclltmetallic conductor which may be adjustedas desired. 85 I At Stm-ting, when the unit is cold, the'rcsistance oftho As the conductor heats it raises the temperature of the unit l5Practically tlltlol the Spiral" AS the unit heats surrounding materialwhich gradually reduces in resist- UP, hOWGVT, the TGSSUMICO 0f th@material'in contact ance and short-circuits the turns ofthe conductor.The with the-conductor dcCrGaSPS and gradually short-cirnal resistanceof the unit will be that of the surround- 35 CUS thc turns 0f theConduC'OI S 21ste automatically ing material at the temperature at whichit is desired v 90 reduce the resistance of the' I Hlit A uuit of thischarthat it shall be used. The cross-section of the sur:4 actor affordsa wide range of adjustment, since thc ierounding material being large,this temperature-need sistance ofthe metallic conductor, spacingaindlongth not necessarily be high, as a very low final specific of theturns may all be adjusted so as toproduce the resistance will not berequired. It will-be seen that 40 desired result. The path throughtheresistance of thc by making the conducting spiral of heavy, stiffmate- 95 second class from one turn of the metallic conductor rial thestrength 0f the stick will be substantially into another isofcomparatively large cross-section so that. creased. Various othermethods ofconstructing this a very low final resistance of the materialis not necesresistance unit will suggest themselves to one' skilledsary. This construction also makes it possible to add in the art. O fcourse, it is not essential that the spiral to the mechanical strengthof the stick. l be on the inside of the tube, nor that a particular mate100V In the accompanying sheet of drawings, I have shown rial, or themethod of arranging the saine be used, the one embodiment of myinvention for purposes of illusimportant feature being the intimaterelationship be` tration but it should be understood that I do not limittween the spiral conductor and a conductor 0f the SGC- the invention tothe particular construction or arrangeond class whereby the lattershort-Circuits the formel ment of parte shown or described, but considermy nupon increase of temperature. 105 ventlon as broad as the scope ofthe claims annexed to what I Claim as new and desire to Secure byLei-,ters and fornlmg apart of thm alphcal'lonf Patent ofthe UnitedStates, is: l The smgle hgure of drawmg represents a' longltudmal 1. Aresistance unit comprising a material having a neg- Sccton of a devl,embodylllg my myellllon- :il'vc temperature coeflicent, and a resistanceconductor Referring'to the drawing, l is a stick'of resistance,Olllbdded Uwln- 110 A resistance unit comprising a selfreducing resistroc'lueing resistance material having an electrical resist/ ancematerial, and a helical resistance conductor, the: :moc conductorembedded therein.

turns of said conductor being in electrical Contact with 6. A rosistnnvnunit comprising n molded stiel: of mate- 15 said material, l'iui having:1 negativo temperni'ure coeicient and 11 helical 3' A resistance unitcmnl'jrjsng a maten-u1 having anotan resiskmce conductor, the suvcossiveturns of which are tive temperature comcent and n resistance conductorsupported hy said sl'irlc :uni in electrical Contact therewith.

having a positive temperature coefficient embedded therein In wiLnwswiwi-co1', I have hereunto sut my hand this 4. A resistance unitComprising :L stick of material huv- '35m' lli." E Nlwmhp", 'm05- ing anegative temperature coeficient und u helical resist- 1) \[1]:1QLL)[AVMILLAN, ance conductor, the successive turns of which are inelecwmmsscs: trical Contact with said stick. my mmx R UMH 5. Aresistance unit comprising u molded stick of seillIlzLi-:N Oni-mur

